Now there's been an update, we need some more votes for features to add in the next version:

WP Snowball: Hot (33 ideas)support.codexplugins.com/forums/216469

Feel free to add others if you think it would benefit.

Here's a feature you may be interested in.Built in KW research tools. This would help in researching your core keywords right from the plugin. We're still thinking over the details on this one, so if you've got any ideas on how you'd like this implemented let me know.